<p>Under conditions of single-sided moisture transfer, concrete displays an uneven distribution of internal relative humidity and creep deformation along its cross-sectional height. This heterogeneity is further intensified by the inclusion of recycled coarse aggregate. In this study, a non-uniform creep model was proposed for recycled concrete under such moisture-transfer conditions. A thermomechanically coupled finite element model was developed to simulate the long-term deformation of recycled concrete, and its accuracy was validated against experimental data. The investigation quantitatively evaluated the effects of key parameters—including the recycled coarse aggregate replacement ratio, loading duration, and humidity boundary conditions—on the non-uniform creep behavior. By incorporating the internal relative humidity profile into a standard uniform creep model, the authors derived an improved distribution model that considered the influence of humidity boundary conditions. Results indicated that both the recycled coarse aggregate replacement ratio and loading duration played crucial roles. Specifically, increasing the replacement ratio from 0 to 100% led to a 39.8–41.4% increase in the top surface creep coefficient and an 86.7–99.6% increase in creep curvature. Moreover, extending the loading period from 90 days to 50 years resulted in a 32.9–79.5% increase in the top surface creep coefficient while simultaneously reduced creep curvature by 34.0–90.0%. The proposed prediction model accurately calculated the creep deformation in recycled aggregate concrete under conditions of single-sided moisture transfer, effectively mitigated prediction inaccuracies caused by moisture gradient effects.</p>